With several articles recently appearing that were based on various aspects of evolutionary psychology, I thought it would be worth taking a closer look.

One of the ironies in examining evolutionary psychology is how many stories we can make up for ourselves without a shred of conclusive evidence, beyond simply sounding plausible. This doesn't mean that they may not be true, but they certainly can't be considered scientific. I thought it would be interesting to examine several points regarding evolutionary psychology before going further:

It is not an area of study, like vision, reasoning, or social behavior. It is a way of thinking about psychology that can be applied to any topic within it. (1)

While this sounds like a very reasonable assessment, it is almost immediately ignored by framing everything that follows as a specific point of study. Five principles are then presented that frame the basis for evolutionary psychology.

Principle 1. The brain is a physical system. It functions as a computer. Its circuits are designed to generate behavior that is appropriate to your environmental circumstances.

The big problem here is in reducing the brain to a computer, which it isn't. While it might be a useful analogy within a very narrow context, it is simply foolish to define biology in terms of recent human technological developments (i.e. computers, machines, etc.). This is simply unacceptable, in the same way that electrons are not like billiard balls, neither is the brain a computer. In truth, there is nothing in the operation of a computer that could find an accurate comparison to the brain's neurobiology (unless one is content to make the comparison simply because signals may be sent electrically). However, by that logic, a television, telephone, and radio are all computers too.

Principle 2. Our neural circuits were designed by natural selection to solve problems that our ancestors faced during our species' evolutionary history.

In this case, the problem occurs with words like "designed", because that already indicates a fundamental failure to understand evolution and natural selection. In the first place, why presume that the brain evolved to "solve problems"? There are organisms that don't even have nervous systems that are capable of that function. More importantly, what problems are so unique to humans that they should be the only species to have "evolved" such a brain? Considering the simple reality that there are no particularly unique problems that humans solve, then we must conclude that this is an insufficient reason to explain the existence of the human brain. It is a classic error in assuming that modern day biological structures are necessarily adaptive. After all, it is equally plausible to assume that brain development diverged due to a random mutation, and that it's subsequent benefits moved humans down a different evolutionary path.

For you, that pile of dung is "disgusting".

Once again, an interesting story, but simply not true. Dung is often used to assess an animal that someone is tracking, and certainly carries vastly different interpretations depending on the animal of origin. In fact, given the cultures which still use dung for fires and fertilizers, this assertion is clearly a product of a modern urban mindset rather than anything to do with human evolution or psychology. This is so basic, that one can't help but marvel at how myopic this "understanding" of human psychology is.

But what did the actual designer of the human brain do, and why? Why do we find fruit sweet and dung disgusting?

This kind of statement is simply embarrassing.

Principle 3. Consciousness is just the tip of the iceberg; most of what goes on in your mind is hidden from you. As a result, your conscious experience can mislead you into thinking that our circuitry is simpler that it really is. Most problems that you experience as easy to solve are very difficult to solve -- they require very complicated neural circuitry

This certainly appears to be true, but I don't see why it's a principle of anything. Once again, it seems much more appropriate to turn this around and argue that the "mind" exists in numerous organisms and it is only recently in human development that consciousness emerged as a trait. I'm not clear why an individual's perception of their personal brain circuitry is of any consequence as a "principle".

...so complex, in fact, that no computer programmer has yet been able to create a robot that can see the way we do.

Doing what comes "naturally", effortlessly, or automatically is rarely simple from an engineering point of view.

It seems like the point is to warn against over-simplifying and yet that's precisely what occurs when words like "engineering" are used to describe a phenomenon which has never been successfully engineered.

Principle 4. Different neural circuits are specialized for solving different adaptive problems.

Interesting idea, but where's the evidence for this? This requires a level of study that simply doesn't exist. In the first place, we have to demonstrate that there are specific psychological responses that are unique to particular adaptive problems. We then have to demonstrate that these behaviors are heritable and governed by neural circuits that fulfill no other more general purpose. This is exceedingly unlikely and the most likely explanation is that our brain is much more flexible than it is specialized to specific problems.

This isn't to say that there aren't specific capabilities that our brain has evolved for, but it is unlikely that they are unique to humans and instead will likely prevail throughout many other mammal's brains. So while we can certainly agree that there are visual or auditory centers in the brain, it is not at all clear that they are uniquely human, nor does it explain anything about how the brain actually maps such sensory data into the context of a "mind" or consciousness.

For example, we all have neural circuitry designed to choose nutritious food on the basis of taste and smell -- circuitry that governs our food choice. But imagine a woman who used this same neural circuitry to choose a mate.

It is also difficult to determine whether these principles are being written as serious definitions or whether they are intended to entertain school children. To suggest that our brain is operating substantively different in choosing food versus choosing mates, indicates such a fundamental misunderstanding about neurobiology, it is mystifying.

Principle 5. Our modern skulls house a stone age mind.

This makes little sense, since it arbitrarily separates "mind" from "brain". After all, this assertion basically argues that evolution has stopped or is unresponsive to human needs. This claim flies in the face of the actual evidence which indicates that humans are a phenomenally adept species and are extremely well adapted to their environment. In fact, the fallacy appears to be based on the notion that somehow we shouldn't experience any challenges, but that rather we should have evolved so that anything we engage in is "effortless". However, it should be obvious that we cannot behave or perform in ways that our brain can't handle. So, while we may personally believe that it isn't as easy as we might wish, there is no evidence to suggest that we aren't adapted to everything we do.

This becomes especially relevant when we want to argue about how our culture has changed us and somehow our behaviors have difficulty keeping pace with those changes. Where is the evidence for this? Is this being assumed simply because of the perception of increased psychological disorders or stresses? Once again, what evidence do we have that such disorders haven't always been present?

Generation after generation, for 10 million years, natural selection slowly sculpted the human brain, favoring circuitry that was good at solving the day-to-day problems of our hunter-gatherer ancestors -- problems like finding mates, hunting animals, gathering plant foods, negotiating with friends, defending ourselves against aggression, raising children, choosing a good habitat, and so on. Those whose circuits were better designed for solving these problems left more children, and we are descended from them.

This statement is simply stupid, because it presumes that we are the hapless victims of a natural selection process that simply can't keep up. It demonstrates a uniform failure to understand that natural selection does not "sculpt" nor "design", but simply ensures that an organism has the necessary traits to survive in the environment in which it exists. No matter how it is considered, the filter of natural selection doesn't only work sometimes. If a species survives (including humans) then it has passed the "selection test". If the point is to argue that our brain is maladaptive, then it requires a bit more than fantasy stories about how cavemen are believed to have lived. It is also curious that of all the attributes listed, virtually none of them are demonstrably "hard-wired". With this kind of basic misunderstanding, it's difficult to assign much credibility to Evolutionary Psychology claims.

After examining these principles and many other points regarding various debating points such as "nature vs nurture" it becomes clear that evolutionary psychology simply isn't ready for prime time, either as a discipline or even as a perspective. In fact, a strong argument can be made that when using evolutionary biology as a perspective in examining behavior there is a real risk of telling oneself convenient stories based on little more than conjecture or imaging what "things must've been like".

Without some insight that is nothing short of miraculous, there is no such thing as evolutionary psychology. So for those that want to insist otherwise, here's the criteria that must be met:

1. Demonstrate that the behavior is neurologically specific enough to be predicted.2. Demonstrate that such behavior is heritable (Note: Learning, by itself, is not sufficient).3. Demonstrate that such heritability actually is adaptive.

These requirements are quite difficult to meet for many aspects of biology, especially that of establishing that a trait is adaptive. However, to glibly toss off explanations based on some arbitrary notion about how early humans lived is simply idle speculation and nonsense.-------------------------(1) All quotes and references come from the Center of Evolutionary Psychology, "The Evolutionary Psychology Primer" http://www.psych.ucsb.edu/research/cep/primer.html

Comments

Comments

Wow - whats up with you these days? Fine, maybe they wrote the text too silly, like about 100% of texts if you really want to criticize every little bit. But your extra strong anti-sympathetic reading of it is just a rant, and I cannot agree with almost anything. They said "functions as a computer", you make something about reducing it to a television out of it. Computer means computing, there are analogue computers, too, and quantum computers, and they all are computers (not blood circuits) because they take information (that can be signals from very different sources (eye, ear, ...)) and then compute. There is nothing wrong with that.After this beginning, it gets worse. You may have some good points here hidden somewhere, but soiled like this, I do not want to dig 'em out.(This is not to defend Evo-Psychology! Psychology has always been too much plausible seeming stories given the social background of the time that made it appear plausible. There should be plenty criticism, but not like this.)

No, this is not Kindergarten, that is why if we want to argue against something and have deep and important points to make, we first give the enemy a sympathetic reading, try to understand why certain terms were used by our enemy (who were they trying to talk to), then maybe even partially take over those terms temporarily in order to show we are sympathetic to their cause and understand what they are trying to say, and then blow the enemy to shreds. I know Gerhard can do that, so I am surprised about this article.

As a result, I expected significantly more than simplistic childish interpretations regarding the basis for why evolutionary psychology should be considered a legitimate perspective on human behavior. What I was particularly struck by was the reasonable point made, in that it serves as a perspective, and then observe how they immediately ignored that perspective and tried to use it to establish "scientific" principles.

They said "functions as a computer", you make something about reducing it to a television out of it. Computer means computing, ...

On this point, I am obviously going to be much more critical. If we're going to be more precise, then even computers barely perform computation. The point of comparing it to a television set, is to illustrate what happens if we focus on those aspects that are truly shared "in common" between these devices. One reason for this, is that invariably many people feel justified in doing so with the brain simply because the brain uses electrical signaling.

However, rather than get into a specific point by point debate about the differences, my real objection is rather simple. I'm put off by scientists using the description of relatively recent modern technologies (like "machines", or "computers") and using it to describe systems that they barely understand. It trivializes the biological system in question and attempts to portray it as an equal or equivalent system to what humans have already developed.

We already know that the phrase was not intended to argue that the brain performs computations, but rather that it resembles the device you have on your desktop (which it doesn't). You are certainly correct if you wish to criticize me for engaging in a rant about it. However, I am opposed to the display of such arrogance, because one of my pet peeves, is that I see complex ideas and problems perpetually being reduced to simplistic meaningless comparisons for no better reason than pandering. The worst part about it, is that it is usually done by individuals that clearly don't understand computers either. Just as an airplane is not a bird, neither is the brain a computer.

I agree with everything Sascha is saying here. Evolutionary psych is deeply flawed by the equal ease with which it can generate plausible-sounding stories to explain any scientific finding and its opposite. That's important, but this article was a silly rant about trivia. Like Sascha, I interpret the word "computer" broadly to mean something that is capable of (usually complex and changeable) computation. And I often struggle to find a good English alternative to the word "design" when I try to talk about evolutionary processes. I'd hate to be condemned for non-scientific thinking because I can't find an English word for design that doesn't imply a designer. And dung? Please, while some societies have a need to use various unpleasant substances for practical purposes, no human society wears fresh dog poop as perfume. I'm surprised the author didn't add complaints about spelling errors to his list of grievances. What a lot of silly nitpicking about unimportant details.

I interpret the word "computer" broadly to mean something that is capable of (usually complex and changeable) computation.

If you don't have a problem with such broad terminology on a site that is supposed to be defining the basis for evolutionary psychology, then I truly don't know what to say. So, I guess it's perfectly fine to argue that a guitar functions like a piano, and believe that something meaningful has been stated.

I'd hate to be condemned for non-scientific thinking because I can't find an English word for design that doesn't imply a designer.

Well, then perhaps it would be inappropriate to write something that is supposed to be scientific. English is not a second language to these people, and such a statement is simply irresponsible.

And dung? Please, while some societies have a need to use various unpleasant substances for practical purposes, no human society wears fresh dog poop as perfume.

... and your point? Remember it was the authors of this primer that wanted to advance an evolutionary argument regarding some selection criteria regarding our attitudes. Your point is irrelevant since no one has argued that dung was attractive, but to presume it has been selected in humans to be disgusting is completely wrong. In the overwhelming majority of cases, it is nothing beyond something that has to be dealt with. All one has to do is observe the typical reaction of "city people" on a farm to understand the distinction. It is a modern societal fetish and has little or nothing to do with evolution or selection.

I'm surprised the author didn't add complaints about spelling errors to his list of grievances.

Perhaps because I don't equate spelling errors with the same seriousness as scientific errors. However, if this site were called "The Center for English Grammar and Spelling", then I certainly would've called them on that.

What a lot of silly nitpicking about unimportant details.

Do tell .... what are the important details? After all, if words can be made to fit whatever message one wants without consequence, and if accuracy isn't necessary, and if examples aren't assessed for correctness .... I can't imagine what you might consider to be important?

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Computer means computing, there are analogue computers, too, and quantum computers, and they all are computers (not blood circuits) because they take information (that can be signals from very different sources (eye, ear, ...)) and then compute. There is nothing wrong with that.
...

There is something very wrong with it. To start with most people think of computers as those strange devices on their desk so the analogy will always be associated with that referent. Yes, computing can be many things but that also highlights another problem. If you are going to define what something is you should choose your analogies very carefully. "Computer", as you state, can mean many things, so when Evol Psych uses the term just what do they mean by it? This type of sloppy thinking pervades Evol Psych.

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Our modern skulls house a stone age mind.
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I'm sick to death of hearing this referent. Brains are incredibly adaptable organs. There's another ambiguity in their definitions - just what is "mind". It is typically a reference to behavior. So they are explaining behavior by using behavior as a causal factor. Odd to say the least. "Mind" is a useless term to describe human cognition. If we truly had stone age minds then why don't I go around bashing up the next door neighbour so I can rape his daughter? If I had a stone age I mind how come I can use this computer? Even visual illusions are contingent on the visual environment of early childhood. Look at the work of Milgram and Zimbardo, the present environment can easily make us very violent. As Milgram noted after his famous experiments - he thought that in order to find suitable people to make up one division of the German WW2 SS he thought he would have to search all over the US. At the end of the experiment he stated New Jersey would be sufficient. Our behavior is not some bottom up process driven by some innate drives as per Freudians and Jungians might entertain, it arises through our interaction with the world. It is not nearly as determined as Evol Psych proponents seem to assert. If we truly did have stone age minds we might have blown up the world many times over. As E.O. Wilson once stated:

"If hamadryas baboons had nuclear weapons they would destroy the world in a week."
From E O Wilson, On Human Nature, 104

Now given the genetic similiarity one would assume ....

....
Our neural circuits were designed by natural selection to solve problems that our ancestors faced during our species' evolutionary history.
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Which ancestors? 20,000 years ago, 100,000 years ago, 5 million years ago?

They said "functions as a computer" in a primer on their webpage. Not sure what's in yours, but my brain has neural networks with neurons having hugely complex dendritic trees and axon arbors and all they do is: compute!
Generally: I am glad psychology gotten finally so far as to understand these things at all. We are talking about a field that is otherwise even worse, so I am glad they at least have some more scientific guidance now via focussing on evolution. That this leads often to nonsense is in this case more to do with psychologists being involved than the fact that it is *evolutionary* psychology.

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Not sure what's in yours, but my brain has neural networks with neurons having hugely complex dendritic trees and axon arbors and all they do is: compute!
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That is trivially obvious. It explains nothing. Descriptors are important, to use descriptors that offer no insight at all to what is happening offers nothing. To use a descriptor that can mislead people into thinking that a brain functions like the everyday device before them is careless. If we want to define what a brain is we should make reference to concepts like volume transmission, polarisation, microglial mediated synaptic pruning, spindle cells, cAMP, A. cyclase, CREB, GABA mediated regulation of the neocortex, frontal lobe anomalies arising from brainstem nuclei lesions, that brains remain remarkable stability in spite of constantly changing internal milieu, that nitric oxide can impact on distant synapses even perturbing axonal transmission, that neurotransmitters do not just travel across a synapse but diffuse widely across to neighbouring cells so even a concept like network can be misleading because it carries with it the idea that neuronal transmission is very discrete; it isn't. If you are not sure what is in my head why do you have any faith in evolution as a useful guide to understanding behavior?

This is good stuff. I am not against some aspects of science being vague, or philosophical, but lumping in everything as some free-for-all means it can't be science. I had a correspondence with Andrea K yesterday and she lamented that everyone claims to know psychology but obviously psychology doesn't police itself very well either and when all crazy hypotheses are equal, outside people will claim validity too. It happens in theoretical physics too, where a bunch of people who do some math twists discovering a paradox means they have uncovered a mystery.

However, next week I am going to have a positive review (yeah, that's right) of an evo psych book even though it incorporates some of what you (and I) dislike above. We still get to examine individual works in their context and this one is good.

I would agree with Gerhard,
Words, their definition and their accuracy, mean everything when you are putting forward ideas - especially scientific ideas. This is why so many academic papers are so challenging to read. The words have been so carefully chosen, mulled over, scrubbed, reviewed in order that, as much as humanly possible, no confusion arises.
I read the source document and while it is entirely possible that they are correct in their principles presenting it the way they did - in such a simplistic, daytime-talk show format - totally destroyed their credibility with me.

Amateur hour here. Picking apart one casually written (and fairly dated) introductory work by picking out generalist sentences? There's a vast library of deeply researched psychology work available in the field of evolutionary biology that you've clearly not investigated. What a waste of time reading this drivel.

You exemplify the problem. You attack people who are critical of EP for good reason instead of attacking the EP people doing schlock, unscientific work that make your field look bad. If you'd like a list of festering pus-filled boils named evo psych 'studies' that infect the skin of actual science, do a 5 second search on this site. Or read anything by Kanazawa, the most popular EP guy in the world.

Certainly Kanazawa is not the most popular guy in EP with anyone in the field. Buss, Miller, Keller, Nettle, Penke, Andrzejczak, etc... these are the important names in EP, driving research.

The author is either not familiar with EP, in which case he shouldn't be writing this article, or he's familiar but ideologically opposed to it so he picked an outdated, casually written single article and holds it up as "the problem with EP" (in which case, again, he shouldn't be writing this article.)

How is this a casually written article? This is touted as a primer on Evolutionary Psychology, authored by two well known and well respected names in the field; Leda Cosmides&John Tooby. It is also on a site called "The Center for Evolutionary Psychology". This isn't exactly a fringe group.

What is disingenuous, is when two people that are considered at the heart of this field, write a piece that is supposed to represent an introduction and overview to the topic, are granted such leeway that even basic biology becomes expendable.

The point wasn't to critique a peer-reviewed paper. It was to take what is supposed to represent "common knowledge" about Evolutionary Psychology, from two researchers that are not on the fringes. If they can't get this part right, then why should I grant them more credence for anything else?

However, let's take a look at Buss "Evolutionary Psychology: A New Paradigm for Psychological Science". What's interesting here, is that he decides that natural selection isn't about increased fitness, since he calls that the "sociobiological fallacy". So, in one simple declaration he determines that humans are not "fitness strivers", but rather "adaptation executors". So now natural selection (that's the evolutionary part of EP) is been changed to eliminate fitness as a criteria.

Hmm .. I guess the existence of cooperation, altruim, helping, conflict, competition, and treachery, don't exist anywhere else in the animal kingdom, so they must be appropriate for human psychology. How about, we consider that any "adaptation" that exists in other animals, must actually precede humans, and consequently is NOT suitable to be separated out as a unique target of evolutionary psychology. In other words, it is only reasonable to invoke evolutionary psychology, if the phenomenon being examined is uniquely human, and is a specific adaptive response to a problem that humans encountered. If the problem has existed before humans, and has been addressed by natural selection in a variety of other species, then it is certainly adaptive behavior, but one can't draw any conclusions about why its manifestation in humans should be considered unique.

Don't get me wrong. There is a good, strong reason why natural selection absolutely must be considered in examining human psychology and its development. However, the problem is much more difficult that most psychologists seem to appreciate, and consequently they end up producing a bunch of trival nonsense, or "just-so" stories.

It's like the assertion about human phobias regarding spiders and snakes. These are quaint stories, but have no basis in reality.

Let's also keep in mind that you can't use learned behaviors, cultural influences, or anything else, unless you can demonstrate that it is heritable, for it to qualify under the "natural selection" heading. This seems to be a uniform failing in virtually every paper.

How about you provide me a paper that you think has provided significant insight into psychology because of natural selection? Then you can see whether my objection is simply ideological or more substantive.

These are supposed to be statements by two of the "pioneers" of Evolutionary Psychology and they can't be bothered to get basic biology correct in their primer? In addition, this is supposed to be a website that is the "Center of Evolutionary Psychology"?

If there's drivel involved, let's go to the original authors (Leda Cosmides&John Tooby). Perhaps you might care to explain why there was so little effort put into defining this "new science", and why so much of it is blatantly incorrect? If the primer is "dated", then perhaps the authors felt that it still reflected an accurate enough portrayal, since the site itself is kept up to date.

I'm also game to have you direct me to a single piece of relevant evolutionary psychology that hasn't been ripped off from older biological theories.

NOTE: I also notice the preponderance of "drivel" associated with "selfish gene" ideas. Gotta love it.

It demonstrates a uniform failure to understand that natural selection does not "sculpt" nor "design", but simply ensures that an organism has the necessary traits to survive in the environment in which it exists.

Also, creationists will take a poor statement like "natural selection slowly sculpted the human brain" and argue that the author is simply substituting "God" with the term natural selection.

Gerhard, I can't believe how confident you are in your conclusion that John Tooby, a man with a PhD in Biological Anthropology from Harvard University, and Leda Cosmides, a woman who earned a bachelors Degree in biology from Harvard in biology with a Magna Cum Laude and who minored in evolutionary biology at Stanford University as a PhD student, have a "simply stupid" understanding of natural selection.

The fact is that their characterization of natural selection is perfectly consistent with Richard Dawkins' explanation of it in The Selfish Gene, which has widespread support among evolutionary biologists.

On the other hand, your contention that "natural selection...simply ensures that an organism has the necessary traits to survive in the environment in which it exists" is too vague to even call wrong, because, among other things, it fails to describe HOW natural selection equips organisms with the traits it needs for survival. Also, I'm pretty sure that all organisms die, so the idea that natural selection ensures that "an" organism survives is a bit weird.

That's the problem. I didn't call Tooby and Cosmides, stupid. I was criticizing the "primer". So you should learn to separate the two. Also, arguing from authority won't get you anywhere. In fact, I chose them specifically because they are not considered on the fringe and therefore their writings were a legitimate target as being considered representative of evolutionary psychology.

The mere fact that you would even cite Dawkin's "selfish gene" theory illustrates that you aren't familiar with the issues, because that is hardly a sufficient explanation. Gene-centric viewpoints have enough difficulties (as does kin selection) to warrant not getting too cocky about it.

There is no HOW to natural selection. Natural selection operates on what you have and if you survive to reproduce (and your offspring survive, etc.), then that's what counts. You're attempting to apply an intent and directionality to evolution that doesn't exist.

Also, I'm pretty sure that all organisms die, so the idea that natural selection ensures that "an" organism survives is a bit weird.

You're joking ... right? Don't parrot other people's ideas if you don't know what they mean.

However, in fairness ... I am more than willing to listen to any scientific explanation in defense of the five (5) principles that I criticized and why they represent a valid assessment of the basis for evolutionary psychology.

First, I did not say that you said Tooby and Cosmides are stupid, I said that you said that their understanding of natural selection is stupid, which you did. I did not twist your words; you twisted mine.

I agree that arguing from authority is a less than ideal way to make a point, but, I'm assuming that you have already read The Selfish Gene and Tooby and Cosmides' Primer, and I'm not sure what ingenious argument I could possibly make in a comment box that would be any more compelling than the ones in those sources. If you are truly curious about the scientific foundation of evolutionary psychology, do not depend on a dude's comments on your blog for that information. There are LOTS of books and peer-reviewed journal articles that you could read about the subject, preferably BEFORE your next assault on the field.
I would personally recommend this one: (http://homepage.psy.utexas.edu/homepage/students/easton/EP_AP.pdf)

Now, I'd like you to look at these words from your response to me: "There is no HOW to natural selection. Natural selection operates..." You can't say that natural selection "operates" and simultaneously say that there is "no how." Obviously, if something operates, then it must operate SOMEHOW.

What's funny is that the "HOW" of natural selection is right in front of your nose: SELECTION! SELECTION IS THE HOW! There is variation in the gene pool, and some genes are more fit to persist - in the form of identical replicas - for much longer than other genes. Thus, some genes (or "alleles" if I must be precise) are selected to persist and become present in larger and larger proportions of the population, while others are selected for elimination. This is where Tooby and Cosmides "sculpting" metaphor comes in. Similar to the way a sculptor crafts an exquisite figure by selecting which pieces of clay (or concrete or whatever) remains on the sculpture and which pieces are removed, natural selection selects (naturally, as opposed to intentionally) which gene's persist and which genes are eliminated. The concept of "design" is commonly evoked to describe the process of natural selection because, though we normally think of design as an intentional process, we could easily think of natural selection as an unintentional form of design - a "blind watchmaker".

Finally, I ADMITTED that I did not know what you meant about natural selection ensuring that organisms possess the traits necessary for survival in their present environment. In fact, I explicitly emphasized its vagueness. I still don't get what you mean......Why do humans prefer the taste of sugary and fatty foods to vegetables? Why do humans bother to bear and rear offspring, rather than devote all their resources towards ensuring their own personal survival? Why do some humans die when they are babies?

What's funny is that the "HOW" of natural selection is right in front of your nose: SELECTION! SELECTION IS THE HOW! There is variation in the gene pool, and some genes are more fit to persist - in the form of identical replicas - for much longer than other genes.

I think you're reading too much into it. Natural selection isn't a "how", it is a "what". An organism lives and reproduces. If something interferes with that reproduction then it won't be represented in the next generation. If the organism dies without reproducing, then it won't be represented in the next generation. Natural selection is a process that describes WHAT is happening, now HOW it happens. Perhaps this is just a dispute over the usage of a word.

Similar to the way a sculptor crafts an exquisite figure by selecting which pieces of clay (or concrete or whatever) remains on the sculpture and which pieces are removed, natural selection selects (naturally, as opposed to intentionally) which gene's persist and which genes are eliminated.

No it doesn't. It eliminates entire organisms. It's an "all or nothing" package and natural selection cannot select "which genes persist". If the organism survives (and reproduces) then all of its genes (good or bad) will persist (at least those that were passed on) and if it doesn't, then none of them will. Even artificial selection can't be that specific, which is why desirable traits often have unintended secondary consequences.

I don't accept the use of the term "design" regardless of its metaphorical intent because it implies an intentionality that simply isn't true.

Why do humans bother to bear and rear offspring, rather than devote all their resources towards ensuring their own personal survival? Why do some humans die when they are babies?

These questions make no sense, and they certainly aren't appropriate for evolutionary psychology. The first question originates with the first single-celled organisms for which there is no good explanation. The most probable speculation is that the first organism that, by chance, replicated gained a sufficient advantage to ensure that all future competitors had to have the same trait. I'm not sure what your second question has to do with anything.

I did not know what you meant about natural selection ensuring that organisms possess the traits necessary for survival in their present environment.

It indicates that natural selection isn't about genes, but about traits and those that are necessary to facilitate survival in the environment the organism currently finds itself in. Traits that are maladaptive or inappropriate become a liability. Just as some dormant trait that had no particular benefit may suddenly surface when the environmental circumstances afford an advantage to its possession.

Gerhard, I enjoyed and appreciated this response. I'd like to say that I half-agree with your contention that "natural selection isn't about genes, but about traits." If you said instead "natural selection is about traits," I would say "I agree." There are several scholars who I have lots of respect for who prefer to think of natural selection as the selection of traits rather than the selection of genes, and that perspective is valid. However, I prefer the "gene's eye view" because we can easily describe how the physical structure of a gene literally gets copied (molecular biologists understand DNA replication pretty well) and preserved across generations. It is a bit more abstract to conceive of how a trait - for instance, fangs- gets preserved across generations.

The question about why some humans die when they're babies was really just a cheap-shot to show that obviously natural selection does not "ensure" that organisms will "survive" (which I guess you are using as a shorthand for "survive until they reproduce.") I shouldn't have included it.

The issue of parental investment, however, is crucial. The fact that animals (especially female mammals) tend to devote considerable amounts of their energy towards rearing their offspring is very strong evidence that natural selection promotes the persistence of genes (or, if you prefer, traits); it does not promote the maximization of individual organisms' longevity. The basic principle is that, for animals' genes (especially those of mammals) to persist in the long-term, they need to program their containing organisms to not only reproduce, but also to help their offspring survive long enough to reproduce offspring of their own. If the offspring don't have their own offspring than the gene is headed towards a "dead end." So, natural selection would favor a gene that simultaneously decreases each of its individual possessors' lifespan and increases the number of (great-great-great-great...)grandchildren that each possesor has. A gene that increases altruism towards offspring would have such effects. We know that animals do in fact sacrifice some of their resources for the benefit of their babies (and other kin), so the significance of gene-preservation in natural selection is confirmed.

I don't buy the altruism argument regarding parental investment, since it is clearly much easier to produce more children, than it is to sacrifice yourself for a particular one. Similarly kin selection is problematic, since it hasn't been demonstrated that there is an adequate level of kin discrimination to provide explanatory power. I know that it's also coupled with limited dispersal, but that's just a catch-all, since if a cause (i.e. kin discrimination) doesn't work, then we can invoke a correlation (i.e. limited dispersal). It answers nothing except to allow for the coincidences.

It would be much better to simply admit that we tend to help those that we "know" regardless of genetic relatedness. In fact, it is easy to see that genetic relatedness is a liability in the long term, so it makes little sense to have much of a basis for altruistic behaviors (as is commonly described).

However, I prefer the "gene's eye view" because we can easily describe how the physical structure of a gene literally gets copied (molecular biologists understand DNA replication pretty well) and preserved across generations.

This is precisely why I dislike the "gene's eye view", because it tends to make it appear that there is a one-for-one relationship between a gene and its expression. Recognizing the importance of traits as the descriptive entity allows one to see that numerous genes may be involved in a particular expression, as well as epigenetic factors, including those that are transmitted through behavioral or cultural channels. Each will have a selective influence on the organism.

NOTE: Let's also bear in mind that genes are not equivalent, since we can have regulatory genes that are responsible for activating switches, and then actual developmental genes that are responsible for structures. In turn, these are heavily influenced by the switches which will govern how a particular gene is expressed. As a result, the "gene's eye view" tends to put all these events together as if they were only a singular occurrence. So, if the same gene can result in a wide range of traits based on its activation process, then what sense does it make to talk about a particular gene as a unit of selection? Only the specific trait that it expressed could possibly be selected, even for the same gene.

Just a quick point about altruism. I think this is one of the most poorly defined concepts that has been introduced into biology. It speaks of the loss of fitness to a relative's gain, and yet fails to address the simple question of whether it is the act that is altruistic or only the behavior.

Even considering Haldane's famous quote, he manages to weasel out of the reality.

He famously said that, "I would lay down my life for two brothers or eight cousins"

In fact this doesn't support altruism at all, because if you only have one brother, then I guess he's just out of luck. Haldane was playing on the mathematics of having to save multiple relatives simultaneously. This would completely fail to take into account behaviors for individuals, one at a time.

Also, consider if two animals behave in identical ways, but one suffers a fitness loss and the other doesn't, is one considered altruistic while the other is not (despite behaving identically)?

It completely fails to address altruism as observed in modern human society.

The question about why some humans die when they're babies was really just a cheap-shot to show that obviously natural selection does not "ensure" that organisms will "survive." I shouldn't have included it.

The issue of parental investment, however, is crucial. The fact that animals (especially female mammals) tend to devote considerable amounts of their energy towards rearing their offspring is very strong evidence that natural selection promotes the persistence of genes across multiple generations; it does not promote the maximization of individual organisms' longevity, or even of each individuals' number of offspring. Parental investment increases an organisms' expected number of grandchildren and great-grandchildren (by increasing the likelihood that the offspring will survive long enough to have their own offspring), but decreases the total number of offspring that an organism can bear, and decreases the expected length of each (parent) organism's life. Cui Bono? The gene's that will be carried along into posterity.

If I may ask for one more response, you said:

"An organism lives and reproduces. If something interferes with that reproduction then it won't be represented in the next generation. If the organism dies without reproducing, then it won't be represented in the next generation."

Could you tell me what the antecedent to the two "it"s is? What won't be represented in the next generation? The organism? Of course the organism won't be represented in the next generation, unless perhaps we're talking about asexual reproduction (which we're not). Reproduction does not cause the organism to persist; it causes (some of) the organisms' genes to persist.

P.S.
You also alluded to the idea that "natural selection is about traits" which I actually think is a legitimate alternative to the "gene's eye view." I'd say that it's true that natural selection selects traits, but it's also true that it selections genes. Maybe we could think of it as two complimentary evolutionary processes happening together: one for genes, and the other for traits.

Any transmissible unit of information. This could be a gene that is actively expressed, or one that is "silent". It could be learned information, or cultural. The point is that nothing that could have originated from that organism will be represented in the next generation.

So, as shorthand, the "it" represents those information units that represent the originating organism. Basically, anything of value (including its genes) that it has to pass on.